A variety of apparatus and methods have heretofore been used in order to cut various patterns from a material which is later to be assembled. For example, the various panels of a jacket maybe designed and drawn on a web of cloth which are then cut out and stitched together to produce the jacket. Another example relates to designing and drawing the various panels on a flexible sheet of material such as vinyl which are cut out and glued or fused together so as to produce a vinyl pool cover.
A variety of cutting apparatus has heretofore been utilized in order to speed up the process and accuracy. One type of cutting apparatus often used is called a wheel cutter or pizza wheel. The wheel cutter generally includes a cutting tool in the form of a cutting wheel having a peripheral cutting edge which rolls on the support surface and moves along a cutting path in cutting engagement with the material. The cutting head can steer the cutting wheel under computer control by rotating the wheel holder about an axis perpendicular to the cutting surface. The cutting wheel and holder may also be castored about the perpendicular axis to allow the natural side forces on the cutting wheel to steer the wheel.
Prior art cutting apparatus have utilized static table cutters. These static table cutters have been commonly used for cutting long pattern pieces or long groups of pattern pieces from rolled goods by means of a cutter head fixed to computer controlled X and Y axis carriages that are driven along the length of long cutting table surface where the carriage is supported on either or both longitudinal edges of the cutting table surface by guide rails affixed to such edges. Computer controlled motors drive X and Y axis carriages to produce the desired motions for cutting selective curves or lines on the cutting surface. The material to be cut is unrolled such that it lays flat on the cutting table surface and is secured by suitable means along the surface. An example of such static table cutter can be found in an article entitled “Pool Maker Adopts Technology From Seafaring Source” published in the September 1992 edition of Aqua which disclosed in part:
(a) computer design of vinyl pool panels;
(b) computer controlled cutting of the vinyl panels;
(c) a cutting machine that rolls back and forth along the table.
Some disadvantage of utilizing static table cutters include:                (a) pattern piece or pattern group length is limited to the length of the cutting table;        (b) the floor space consumption (footprint) is proportional to the longest expected pattern piece or group        (c) considerable operator intervention is required to lay down the material properly prior to cutting and removing the cut pieces and scrap after cutting;        (d) the material must be secured over a large area; and if vacuum retention is used, this becomes relatively expensive;        (e) much of the complexity for motor and cutter control must be carried either on the carriage or cable to the carriage along cable tracks.        
In either case such arrangement adds mass to the overall design. The total cutting time is the time it takes the cutting head to cut the pieces plus the time required to lay down the material and pick up the cut pieces.
Another arrangement used in the prior art includes conveyorized cutters. Conveyorized cutting apparatus generally include one or more cutting heads each which is suspended above the material affixed to one or more X and Y carriages generally in the same manner as static tables cutters. However, in the conveyorized cutting systems the cutting surface is the upper surface of a closed loop link conveyor. The length of the conveyor can generally be two to three times the width of the cutting surface. Material is pulled from a stationary roll unto the cutting area and the material may be retained to the bed by a vacuum that acts through the top of the bed. The pattern pieces may be cut and the conveyor then advances again to remove the cut pieces and scrap and at the same time pulling material unto the cutting area. Normally the conveyor bed is stationary during cutting but cutting heads may be used to operate while the conveyor bed is moving. In this case the motion of both must be co-ordinated by the computer to provide the desired cut paths.
Conveyorized cutting apparatus also include a variety of draw backs which include:
(a) greater complexity;
(b) the sustained speed of processing of the cut pieces is limited to the maximum speed of the conveyor, normally less than 12″ per second;
(c) more complicated vacuum support system;
(d) cutting surface is generally limited to or compliant to present an endless loop and therefore not rigid. The conveyor bed must be flexible in order to lay flat in the cut zone and also be able to complete a circuit or loop such that the conveyor forms a closed loop. This adds mass and cost to the conveyor, while reducing stability.
An example of such computerized cutting apparatus may be found in a flyer distributed by Eastman entitled “Eastman EC3” distributed in 1997.
Moreover, other cutting systems can be found in U.S. Pat. No. 3,614,369 which discloses cloth continuously moved under tension through a cutting zone, and cut by means having applied to it a component of motion oblique to the direction of movement of cloth. Movement of the cutter may be controlled by program means such as magnetic tapes which feed information by a computer and feedback means for controlling the position of the cutter.
It is an object of this invention to provide an improved method and apparatus for cutting pattern pieces from continuous rolled goods.